With a conventional pruning saw blade, the pruning saw blade contains a cutting edge on only one side of a blade main body. Therefore, when the saw blade is used to cut a limb or branch, as the limb is sawed from the top, the limb will sag under its own weight and will eventually fall down prior to the saw blade cutting the entire way through the limb. Therefore, the branch or limb will split which will injure the tree rather than if the limb were completely sawed through.
In addition, with a conventional pruning saw blade, if the saw blade becomes disengaged from the limb prior to completion of cutting the limb, it is often difficult to center the saw blade on the cut again, especially if the limb is high up.